Nodal line semimetal states in positive electrode material of lead-acid battery: Lead dioxide family and its derivatives

TL;DR

This study predicts three-dimensional nodal line semimetal phases in lead dioxide materials and derivatives using first-principles calculations, revealing their topological properties and potential for spintronic applications.

Contribution

It introduces the realization of nodal line semimetal phases in lead dioxide family materials through symmetry analysis and first-principles calculations, including strain-tunable phases and derivatives.

Findings

Beta-PbO2 features orthogonal nodal rings protected by mirror symmetry.

Nodal lines mainly originate from oxygen p orbitals and are robust against spin-orbit coupling.

Strain can induce a topological phase transition in alpha-PbO2.

Abstract

Based on first-principles calculations and symmetry analysis, we report that the three-dimensional (3D) nodal line (NL) semimetal phases can be realized in the lead dioxide family (\emph{$\alpha$}-PbO$_2$ and \emph{$\beta$}-PbO$_2$) and its derivatives. The \emph{$\beta$}-PbO$_2$ features two orthogonal nodal rings around the Fermi level, protected by the mirror reflection symmetry. The effective model is developed and the related parameters are given by fitting with the HSE06 band structures. The NLs mainly come from the $p$ orbitals of the light element O and are rather robust against such tiny spin-orbit coupling. The NL phase of the \emph{$\alpha$}-PbO$_2$ can be effectively tailored by strain, making a topological phase transition between a semiconductor phase and a NL phase. In addition, the exploration of \emph{$\beta$}-PbO$_2$ derivatives (i.e. \emph{$\beta$}-PbS$_2$ and \emph{$\beta$}-PbSe$_2$) and confirmation of their topological semimetallicity greatly enrich the NL semimetal family. These findings pave a route for designing topological NL semimetals and spintronic devices based on realistic PbO$_2$ family.